This study analyzed the relationship between distribution of Bolboschoenus planiculmis which is main food source of swans (national monument species) with environmental factors, discharge, rainfall, and salinity in Eulsuk-do from 2020 to 2023. The distribution area of B. planiculmis in Eulsuk tidal flat was 103,672 m2 in 2020, 95,240 m2 in 2021, 88,163 m2 in 2022, and 110,879 m2 in 2023, and represents a sharp decrease compared to the 400,925 m2 area recorded in 2004. From 2020 to 2023, the growth densities of B. planiculmis were 243.6±12.5 m-2, 135.45±7.38 m-2, 51.10±2.54 m-2, and 238.20±16.36 m-2, respectively, and the biomass was 199.89±28.01 gDW m-2, 18.57±5.12 gDW m-2, 6.55±1.12 gDW m-2, and 153.53±25.43 gDW m-2 in 2020, 2023, 2021, and 2022, respectively. Based on discharge during May~July, which affects plant growth, the left gate discharge of the estuary barrage from 2020 to 2023 was 62,322 m3 sec-1, 33,329 m3 sec-1, 6,810 m3 sec-1, and 93,641 m3 sec-1, respectively; rainfall was 1,136 mm, 799 mm, 297 mm, and 993 mm, respectively; and average salinity was 14.7±9.4 psu, 21.1±4.7 psu, 26.1±2.7 psu, and 14.5± 11.1 psu, respectively. In 2022, cumulative rainfall (978 mm, about 70% of the 30-year average) and discharge (43,226 m3 sec-1) decreased sharply, resulting in the highest mean salinity (25.46 psu), and the distribution area, density, and biomass of the B. planiculmis decreased sharply. In 2023, there was a rise in discharge with an increase in rainfall, leading to a decrease in salinity. Consequently, this environmental change facilitated the recovery of B. planiculmis growth.

This study was conducted to investigate the current status of seagrass species in the Nakdong River estuary from May to June 2023. To survey the seagrass habitat area, the Nakdong River estuary was divided into seven zones. Aerial photography using drones was conducted to find seagrass areas, GPS tracking was carried out on foot in the intertidal zone and by boat and SCUBA diving in the subtidal zone. To analyze the seagrass status, we measured the morphological characteristics, shoot density, and biomass of representative seagrass species in each zone. Four seagrass species were found in this area: Zostera japonica, Z. marina, Ruppia maritima, and Phyllospadix japonicus. The distribution areas of each species was 338.2 ha, 92.9 ha, 0.9 ha, and 1.4 ha, respectively, with a total area of 432.5 ha. Z. japonica was widely distributed in most of the tidal flats and mudflats of the Nakdong River estuary, while Z. marina was restricted to Nulcha-do, Jinu-do, and Dadae-dong. R. maritima occurred within the habitat of Z. japonica in Eulsukdo and Myeongji mudflats, and P. japonicus inhabited rocky areas in Dadae-dong. The shoot density of each species was 4,575.8±338.3 shoots m-2, 244.8±12.0 shoots m-2, 11,302.1±290.0 shoots m-2, and 2862.5±153.5 shoots m-2, respectively. The biomass of each species was 239.7±18.5 gDW m-2, 362.3±20.5 gDW m-2, 33.3±1.2 gDW m-2, and 1,290.0±37.0 gDW m-2, respectively. The results of this study revealed that Z. japonica was dominant in the Nakdong River estuary. In particular, Z. japonica habitats of Eulsukdo, Daema-deung, and Myeongji mudflats were identified as the largest in Korea. The Nakdong River estuary is an important site of ecological, environmental, and economic value, and will require continuous investigation and management of the native seagrasses.

Bolboschoenus planiculmis has been acknowledged as a key species in whooper swans (Cygnus cygnus) habitat by providing food for this migratory waterfowl. B. planiculmis wetlands are being degraded by water shortages and salinization caused by anthropogenic activities and climate changes. In 2004, the distribution of B. planiculmis in the tidal flats of the Nakdong Estuary was 2,475,568 m2, and in 2021, the distribution area was 798,731 m2, which decreased by 32.3%. In order to restore the degraded B. planiculmis wetlands, shoot transplantation and seed sowing were tentatively used in three places with different salinity and water levels. The average density per unit area in September at the optimal growth period after planting were A (fresh water level 50 cm) 58±15.65 m-2, B (brackish water level 0~5 cm) 188±63.83 m-2, C (brackish water level 0 cm or less) 188±45.13 m-2. The tubers were observed as A 0 g dw m-2, B 25.32±2.94 g dw m-2, and C 13.39±0.91 g dw m-2. Tubers were distributed in the soil, with only 3.0% at the 10~20 cm depth but 97.0% at the 0~10 cm depth. In contrast, the germination rate of B. planiculmis seeds was observed to be 0%. Results of this study provide technical support for the restoration of B. planiculmis wetland and the improvement in the quality of whooper swans habitat.

최근 대추에 장님노린재에 의한 피해가 발생함에 따라 대추재배 농가들이 적절한 방제를 할 수 있도록 시기별 발생 밀도, 우점종 조사, 방제 가능 약제 선발 등의 시험을 수행하였다. 대추과원에서 발생하는 장님노린재의 발생 밀도를 2년에 걸쳐 조사한 결과, 약충은 5월 상순부터 발생 하여 7월 중순까지 발생 하였으며, 성충은 5월 하순부터 발생하여 7월 중하순까지 발생하였다. 또한 대추과원에서 발생하는 애무늬고리장님노린재와 초록장님노린재의 밀도의 경우 45개체 중 40개체가(약 89%) 애무늬고리장님노린재 인 것으로 조사되어 대추나무를 가해하는 장님노린재 중 우점종은 애무늬고리장님노린재 인 것으로 나타났다. 대추과원에서 장님노린재 방제에 활용할 수 있는 살충제에 관한 정보를 제공하기 위해 9 종 살충제들을 대상으로 한 야외시험에서 pyrifluquinazon, deltamethrin, diazinon, dinotefuran, etofenprox, fenitrothion, bifenthrin 7종 이 80% 이상 살충력을 나타냈다. 따라서 본 시험에서 조사된 살충제를 이용하여 대추나무 발아 직전부터 방제를 하면 대추과원에서 장님노린재 방제가 가능 할 것으로 판단된다.

본 연구는 충청북도농업기술원 대추연구소에서 보유 중인 대추 유전자원 중 형태적 다형성을 나타내는 ‘일본’과 주요 대추 유전자원의 형태형질을 조사하고, 대추 육종 소재로서 ‘일본’의 가능성을 확인하기 위해 수행되었다. ‘일본’은 주요 대추 유전 자원과 비교하여 엽과 과실의 크기가 뚜렷하게 작고 당도가 낮았다. 하지만 과실에 폴리페놀 함량이 가장 높았으며, 항산화 능력 또한 가장 높았다. 또한 ‘일본’은 종자형성능이 가장 높았다. 대추 유전자원들의 형태형질을 이용하여 분석한 결과, 지리적 기원에 따라 유전자원들이 분류되었다. 특히 ‘일본’은 한국 및 중국 유전자원들과 명확히 구분되었다. 따라서 종자형성능이 우수하고 기능성 성분이 높은 ‘일본’은 추후 대추 유전연구 및 교배육종을 통한 품종 육성에 유용하게 이용될 수 있을 것으로 생각된다.

Background: Recently, jujube (Zizyphus jujuba Mill.) has been attracting attention as a fruit, and its cultivation in rain shelter house is increasing to produce the high quality fresh jujube. This study was carried out to investigate the growth and fruit characteristics of jujube according to the types of rain shelter house. Methods and Results: The characteristics of 5-year-old Bokjo cultivar cultivated in 3 types of rain shelter house, multi span rain shelter house with roof vent (Type I), single span house with a column in the center and roof vent (Type II) and single span house with a column in the center and without roof vent (Type III), and open field were examined. The sprouting and blooming period were different among the types of rain shelter house. The diameter of main stem was higher in rain shelter houses than in the open field. There was no a significant difference in fruit number per leaf stem among the types of cultivation. The incidence of fruit cracking in open field cultivation which was 51.2% was much higher than that in Type I 21.6%, Type II 19.3%, and Type III 25.5%. The fruit size and weight in rain shelter houses, especially in Type III rain shelter house were higher than those in the open field and the soluble solids content of fruit in Type I and Type II was higher than in Type III rain shelter house and the open field. Conclusions: The results show that the growth and fruit quality of jujube were improved by cultivation in rain shelter house, and affected by the types of rain shelter house.

The objective of this study was to analyze correlation between phenological characteristics of Salix spp. and meteorological factors in the Upo wetlands. Phenology of Salix subfragilis Andersson and Salix chaenomeloides Kimura was monitored from 2007 to 2012. Meteorological variables were monitored by Korea Meteorological Administration (Hap-chon). Average date of flowering, fruiting, seed dispersion was 86, 113, 136 days for S. subfragilis and 112, 140, 164 days for S. chaenomeloides as Julian days. Flowering of S. subfragilis and S. chaenomeloides were correlated with daily mean air temp. in March (r=-0.92, r=-0.85, p<0.05). Fruiting of S. subfragilis was correlated with total precipitation between Jan and March of previous year (r=-0.90, p<0.01), however, the fruiting of S. chaenomeloides was highly correlated with max. temp. in Jan of previous year (r=0.99, p<0.01). Seed dispersion of both species is correlated with min. temp. in Feb. Phenology monitoring will contribute to understanding Salix spp. response against climate change.